[gmx-users] cg and contraints error

[Yang Ye]

simply all spc/tip3p water uses settle, a variation of shake constraint.

Yang Ye

Sampo Karkola wrote:
> Hi!
>
> I was trying to do energy minimisation using cg after a succesful 
> minimisation with steepest descent. I get fatal error from grompp 
> complaining about constraints
>
> ***************************
> creating statusfile for 1 node...
>
> Back Off! I just backed up mdout.mdp to ./#mdout.mdp.4#
> checking input for internal consistency...
> calling /lib/cpp...
> processing topology...
> Generated 182 of the 1128 non-bonded parameter combinations
> Excluding 3 bonded neighbours for Protein 1
> Excluding 2 bonded neighbours for SOL 11316
> Excluding 1 bonded neighbours for NA+ 40
> Excluding 1 bonded neighbours for CL- 41
> processing coordinates...
> double-checking input for internal consistency...
> ERROR: can not do Conjugate Gradients with constraints (33948)
> Fatal error: There was 1 error
> *************************
>
> In my mdp file I have constraints = none and FLEX_SPC water included. 
> In one of the mailing list answers there was a suggestion that the 
> constraints are hardcoded to topology followed by a question if there 
> any dummies in the topology. What does this hardcoding mean? I do not 
> have any dummies in the topology.
>
> Thanks,
>
> Sampo
>